Symptom improvement after upgrade from right ventricular apical to biventricular pacing: Role of right and left ventricular volumes assessed with single-photon emission computed tomographic equilibrium radionuclide angiocardiography

Abstract

Background: In patients with heart failure and reduced left ventricular ejection fraction (LVEF), the effect of upgrading from right ventricular (RV) apical to biventricular pacing on RV and left ventricular (LV) volumes and ejection fraction (EF) is unknown. Also, the relationship of symptom improvement after biventricular upgrade to RV and LV volumes and EF has not been clarified.

Methods and results: Nineteen patients with long-standing persistent RV apical pacing who had heart failure symptoms and echocardiographic LVEF of 0.40 or less underwent upgrade to biventricular pacing. Patients had single-photon emission computed tomographic equilibrium radionuclide angiocardiography immediately before and at 3-6 months after the upgrade procedure, to measure RV and LV volumes and EF. Biventricular upgrade was associated with increase in LVEF and decrease in LV end-diastolic and end-systolic volumes; right ventricular ejection fraction (RVEF) and end-diastolic and end-systolic volumes were unaltered. Patients with improvement in New York Heart Association heart failure class of I or more had larger initial LV end-diastolic volumes than patients without an improvement and had decreased LV end-diastolic and end-systolic volumes comparatively. Symptom improvement was not associated with RVEF and volume change.

Conclusion: Symptom improvement with LV remodeling, but not RV remodeling, occurs 3-6 months after biventricular upgrade in patients with heart failure.